AT boots can be more comfortable for touring but if you are using this system you should use something that is compatible with the DIN standard. An AT boot with a rockered lugged sole will not release as reliably from a standard DIN alpine binding and may not fit due to the different toe height that the rockered sole causes. There are options like the Black Diamond Factor, Garmont Endorphin, and Scarpa Hurricane Pro that have soles that work with alpine bindings. There are also alpine boot manufacturers that produce boots that include some sort of walk mode. On this type of set up the main differences you would see between an alpine boot and an AT boot is the weight of the boot and the releasable cuff. Having a cuff with a walk mode can make the climb go easier but I have a friend who tours in Lange RS 140 boots too so you can make just about anything work. If you are using this plate with an alpine binding on most likely a less backcountry oriented ski weight probably isn't your biggest concern. Sorry I don't know about the answer to your first question but I hope this helps.